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Acceleration of quantum decay processes by frequent observations

Abstract

In theory, the decay of any unstable quantum state can be inhibited by sufficiently frequent measurements—the quantum Zeno effect1,2,3,4,5,6,7,8,9,10. Although this prediction has been tested only for transitions between two coupled, essentially stable states5,6,7,8, the quantum Zeno effect is thought to be a general feature of quantum mechanics, applicable to radioactive3 or radiative decay processes6,9. This generality arises from the assumption that, in principle, successive observations can be made at time intervals too short for the system to change appreciably1,2,3,4. Here we show not only that the quantum Zeno effect is fundamentally unattainable in radiative or radioactive decay (because the required measurement rates would cause the system to disintegrate), but also that these processes may be accelerated by frequent measurements. We find that the modification of the decay process is determined by the energy spread incurred by the measurements (as a result of the time–energy uncertainty relation), and the distribution of states to which the decaying state is coupled. Whereas the inhibitory quantum Zeno effect may be feasible in a limited class of systems, the opposite effect—accelerated decay—appears to be much more ubiquitous.

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Figure 1: The QZE characteristics and a frequent-measurement scheme.
Figure 2: The AZE characteristics and a frequent-measurement scheme for two-level systems.

References

  1. 1

    Khalfin, L. S. Phenomenological theory of K0 mesons and the non-exponential character of the decay. JETP Lett. 8, 65 –68 (1968).

    ADS  Google Scholar 

  2. 2

    Misra, B. & Sudarshan, E. C. G. The Zeno's paradox in quantum theory. J. Math. Phys. 18, 756– 763 (1977).

    ADS  MathSciNet  Article  Google Scholar 

  3. 3

    Sakurai, J. J. Modern Quantum Mechanics 484–486 (Addison-Wesley, Reading, Massachusetts, 1994).

    Google Scholar 

  4. 4

    Joos, E. Continuous measurement: Watchdog effect versus golden rule. Phys. Rev. A 29, 1626–1633 (1984).

    ADS  MathSciNet  Google Scholar 

  5. 5

    Cook, R. J. What are quantum jumps? Phys. Scr. T 21, 49–51 (1988).

    ADS  Article  Google Scholar 

  6. 6

    Itano, W. M., Heinzen, D. J., Bollinger, J. J. & Wineland, D. J. Quantum Zeno effect. Phys. Rev. A 41, 2295 –2300 (1990).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Knight, P. L. Watching a laser hot-pot. Nature 344, 493 –494 (1990).

    ADS  Article  Google Scholar 

  8. 8

    Frerichs, V. & Schenzle, A. Quantum Zeno effect without collapse of wave packet. Phys. Rev. A 44, 1962– 1968 (1991).

    ADS  CAS  Article  Google Scholar 

  9. 9

    Schulman, L. S. Continuous and pulsed observations in the quantum Zeno effect. Phys. Rev. A 57, 1509–1515 (1998).

    ADS  CAS  Article  Google Scholar 

  10. 10

    Facchi, P. & Pascazio, S. Temporal behavior and quantum Zeno time of an excited state of the hydrogen atom. Phys. Lett. A 241, 139–144 (1998).

    ADS  CAS  Article  Google Scholar 

  11. 11

    Fearn, H. & Lamb, W. E. Jr Computational approach to the quantum Zeno effect: Position measurements. Phys. Rev. A 46, 1199–1205 ( 1992).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Kofman, A. G. & Kurizki, G. Quantum Zeno effect on atomic excitation decay in resonators. Phys. Rev. A 54, R3750 –R3753 (1996).

    ADS  CAS  Article  Google Scholar 

  13. 13

    Cohen-Tannoudji, C., Dupont-Roc, J. & Grynberg, G. Atom-Photon Interactions (Wiley, New York, 1992).

    Google Scholar 

  14. 14

    Milburn, G. J. Quantum Zeno effect and motional narrowing in a two-level system. J. Opt. Soc. Am. B 5, 1317–1322 (1988).

    ADS  Article  Google Scholar 

  15. 15

    Moses, H. E. Exact electromagnetic matrix elements and exact selection rules for hydrogenic atoms. Lett. Nuovo Cimento. 4, 51– 53 (1972).

    Article  Google Scholar 

  16. 16

    Beige, A. & Hegerfeldt, G. C. Quantum Zeno effect and light-dark periods for a single atom. J. Phys. A 40, 1323–1334 (1997).

    ADS  MathSciNet  Article  Google Scholar 

  17. 17

    Harel, G., Kofman, A. G., Kozhekin, A. & Kurizki, G. Control of non-Markovian decay and decoherence by measurements and interference. Opt. Express 2, 355–367 (1998).

    ADS  CAS  Article  Google Scholar 

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Acknowledgements

G.K. is the G. Dunne Professor of Chemical Physics, A.K. is supported by the Israel Ministry of Absorption. This work was supported by the ISF, Minerva and EU (TMR).

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Correspondence to G. Kurizki.

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Kofman, A., Kurizki, G. Acceleration of quantum decay processes by frequent observations. Nature 405, 546–550 (2000). https://doi.org/10.1038/35014537

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